// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// AudioInputDeviceManager manages the audio input devices. In particular it
// communicates with MediaStreamManager and AudioInputRendererHost on the
// browser IO thread, handles queries like
// enumerate/open/close/GetOpenedDeviceInfoById from MediaStreamManager and
// GetOpenedDeviceInfoById from AudioInputRendererHost.
// The work for enumerate/open/close is handled asynchronously on Media Stream
// device thread, while GetOpenedDeviceInfoById is synchronous on the IO thread.

#ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_H_
#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_H_

#include <map>
#include <vector>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/threading/thread.h"
#include "build/build_config.h"
#include "content/browser/renderer_host/media/media_stream_provider.h"
#include "content/common/content_export.h"
#include "content/common/media/media_stream_options.h"
#include "content/public/common/media_stream_request.h"

namespace media {
class AudioManager;
}

namespace content {

class CONTENT_EXPORT AudioInputDeviceManager : public MediaStreamProvider {
public:
    // Calling Start() with this kFakeOpenSessionId will open the default device,
    // even though Open() has not been called. This is used to be able to use the
    // AudioInputDeviceManager before MediaStream is implemented.
    // TODO(xians): Remove it when the webrtc unittest does not need it any more.
    static const int kFakeOpenSessionId;

    explicit AudioInputDeviceManager(media::AudioManager* audio_manager);

    // Gets the opened device info by |session_id|. Returns NULL if the device
    // is not opened, otherwise the opened device. Called on IO thread.
    const StreamDeviceInfo* GetOpenedDeviceInfoById(int session_id);

    void Unregister();

    // MediaStreamProvider implementation, called on IO thread.
    void Register(MediaStreamProviderListener* listener,
        const scoped_refptr<base::SingleThreadTaskRunner>&
            device_task_runner) override;
    int Open(const StreamDeviceInfo& device) override;
    void Close(int session_id) override;

#if defined(OS_CHROMEOS)
    // Registers and unregisters that a stream using keyboard mic has been opened
    // or closed. Keeps count of how many such streams are open and activates and
    // inactivates the keyboard mic accordingly. The (in)activation is done on the
    // UI thread and for the register case a callback must therefor be provided
    // which is called when activated.
    // Called on the IO thread.
    void RegisterKeyboardMicStream(const base::Closure& callback);
    void UnregisterKeyboardMicStream();
#endif

private:
    typedef std::vector<StreamDeviceInfo> StreamDeviceList;
    ~AudioInputDeviceManager() override;

    // Opens the device on media stream device thread.
    void OpenOnDeviceThread(int session_id, const StreamDeviceInfo& info);

    // Callback used by OpenOnDeviceThread(), called with the session_id
    // referencing the opened device on IO thread.
    void OpenedOnIOThread(int session_id, const StreamDeviceInfo& info);
    // Callback used by CloseOnDeviceThread(), called with the session_id
    // referencing the closed device on IO thread.
    void ClosedOnIOThread(MediaStreamType type, int session_id);

    // Verifies that the calling thread is media stream device thread.
    bool IsOnDeviceThread() const;

    // Helper to return iterator to the device referenced by |session_id|. If no
    // device is found, it will return devices_.end().
    StreamDeviceList::iterator GetDevice(int session_id);

#if defined(OS_CHROMEOS)
    // Calls Cras audio handler and sets keyboard mic active status.
    void SetKeyboardMicStreamActiveOnUIThread(bool active);
#endif

    // Only accessed on Browser::IO thread.
    MediaStreamProviderListener* listener_;
    int next_capture_session_id_;
    StreamDeviceList devices_;

#if defined(OS_CHROMEOS)
    // Keeps count of how many streams are using keyboard mic.
    int keyboard_mic_streams_count_;
#endif

    media::AudioManager* const audio_manager_; // Weak.

    // The message loop of media stream device thread that this object runs on.
    scoped_refptr<base::SingleThreadTaskRunner> device_task_runner_;

    DISALLOW_COPY_AND_ASSIGN(AudioInputDeviceManager);
};

} // namespace content

#endif // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_DEVICE_MANAGER_H_
